linux-kernel - Re: Virt: Kvm - Fix possible ERR

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Tue, 20 Sep 2016 10:36:35 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Shailendra Verma <shailendra.v@...sung.com>,
        Gleb Natapov <gleb@...nel.org>, kvm@...r.kernel.org,
        Ravikant Sharma <ravikant.s2@...sung.com>
Cc:     linux-kernel@...r.kernel.org, vidushi.koul@...sung.com
Subject: Re: Virt: Kvm - Fix possible ERR_PTR() dereferencing.



On 20/09/2016 08:50, Shailendra Verma wrote:
> This is of course wrong to call kfree() if memdup_user() fails,
> no memory was allocated and the error in the error-valued pointer
> should be returned.
> 
> Reviewed-by: Ravikant Sharma <ravikant.s2@...sung.com>
> Signed-off-by: Shailendra Verma <shailendra.v@...sung.com>
> ---
>  virt/kvm/kvm_main.c | 20 ++++++--------------
>  1 file changed, 6 insertions(+), 14 deletions(-)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 484079e..e3a0653 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2398,10 +2398,8 @@ out_free1:
>  
>  		r = -ENOMEM;
>  		kvm_regs = memdup_user(argp, sizeof(*kvm_regs));
> -		if (IS_ERR(kvm_regs)) {
> -			r = PTR_ERR(kvm_regs);
> -			goto out;
> -		}
> +		if (IS_ERR(kvm_regs))
> +			return PTR_ERR(kvm_regs);

This incorrectly skips the vcpu_put at the end.

Paolo

>  		r = kvm_arch_vcpu_ioctl_set_regs(vcpu, kvm_regs);
>  		kfree(kvm_regs);
>  		break;
> @@ -2422,11 +2420,8 @@ out_free1:
>  	}
>  	case KVM_SET_SREGS: {
>  		kvm_sregs = memdup_user(argp, sizeof(*kvm_sregs));
> -		if (IS_ERR(kvm_sregs)) {
> -			r = PTR_ERR(kvm_sregs);
> -			kvm_sregs = NULL;
> -			goto out;
> -		}
> +		if (IS_ERR(kvm_sregs))
> +			return PTR_ERR(kvm_sregs);
>  		r = kvm_arch_vcpu_ioctl_set_sregs(vcpu, kvm_sregs);
>  		break;
>  	}
> @@ -2514,11 +2509,8 @@ out_free1:
>  	}
>  	case KVM_SET_FPU: {
>  		fpu = memdup_user(argp, sizeof(*fpu));
> -		if (IS_ERR(fpu)) {
> -			r = PTR_ERR(fpu);
> -			fpu = NULL;
> -			goto out;
> -		}
> +		if (IS_ERR(fpu))
> +			return PTR_ERR(fpu);
>  		r = kvm_arch_vcpu_ioctl_set_fpu(vcpu, fpu);
>  		break;
>  	}
>